We may have found other answers which could help you.
Click here for Tension Sewing MachineToyota SL3404D Overlocker leaving big loops?
How to switch on light of sewing machine?
Sewing machine issue?
Sew-tric ltd variable speed motor built 1982 6000rpm r007327?
How do fill a bobber?
Singer zigzag 457 Stylist not threading bobbin/making stitch?